Immunomodulator Galectin-9 is Increased in Blood and Skin of Patients with Bullous Pemphigoid

Massive recruitment of eosinophils into the dermis is a hallmark of bullous pemphigoid pathogenesis. Identi?fying the chemoattractant(s) guiding eosinophils into the skin in bullous pemphigoid is a prerequisite to thera?peutic targeting of eosinophil recruitment. Galectin ?9 is a potent chemoattractant for eosinophils, but its potential role in bullous pemphigoid is unknown. The aim of this study was to determine the expres?sion levels of galectin?9 in serum and skin of patients with bullous pemphigoid. Galectin?9 levels were sig?nificantly elevated in serum of patients with bullous pem phigoid compared with age? and sex?matched con?trols, but did not correlate with disease activity asses?sed with the Bullous Pemphigoid Disease Area Index. Galectin?9 expression was also increased in lesional skin of patients with bullous pemphigoid, and was ex?pressed predominantly in eosinophils, neutrophils and keratinocytes. In conclusion, these results support the notion that galectin?9 may play a role in the patho?genesis of bullous pemphigoid.